Screed construction for road finishing machines



June 20, 1944. H REER l 2,351,593 I SCREED CONSTRUCTION FOR'` ROAD FINISHING MACHINES Filed Aug. 1, 1940 4 Sheets-Shgef 1 l @fr H B 0115er' June 20, 1944. H. H. BARBER Y 2,351,593

Y SOREED CONSTRUCTIONFOR ROAD FINISHING MACHINES Filed Au'g. 1. 1940 4 Sheets-Sheet 2 H I l Y r- Harry H- dfbe June 20, 1944. BARBER 2,351,593

sOREED CONSTRUCTION FOR ROAD FINISHING MACHINES Filed Aug. 1, 1940 4 Sheets-Sheet 3 fl 5 5 El 6 50 ,f2 Lk l '+3 LI9 I7 35 40 53 y n@ lf/ 53o. I 38 \lllllllllgllll MMBIMMMMBBM!Ml!!! m DF Hal/ffy afel.

iwf @mm June 20, 1944. H, BARBER 2,351,593, y scREED CONSTRUCTION FOR ROAD FINISHING MACHINES Filed Aug. 1. 1940 4 Sheets-Sheet -4 `EJQ Q' #A RR x/z BARBER y ha @MW-@ Patented June 2o, 1944 SCREED CONSTRUCTION FOR ROAD FINISHmG MACHINES Harry H. Barber, Aurora, Ill., assigner to Barber- Greene Company, Aurora, Ill., a corporation of Illinois Application August 1, 1940, Serial No. 349,038

13 claims.

This invention relates to improvements in screed assemblies for material laying machines whereby the laid material can be crowned to the desired extent, made perfectly flat, or formed with a depression or basin without interchanging parts of the machine. More specifically, the invention relates to the division of screed assemblies for road finishing machines into two hinged together units which are quickly adjustable and yet rigid in their adjustment for controlling the contour of a road being laid.

'While theinvention is adapted for screed or ironing and smoothing devices of material laying machines generally, it will be hereinafter described specically as applied to road finishing machines of the type disclosed and claimed in my U. S. Letters l Patent Nos. 2,138,828 and 2,168,507.

'Road iinishing machines are generally constructed so as to lay a mat of finished road about ten feet in width. It is desirable to be able to crown this ten foot wide mat in order to conform with the surface contour of the pavement. Ac-

cording to this invention the crowning is obtained by dividing the screed assembly into two five foot sections and by hinging the sections together through a sealed joint hinge which will not open up to leave a ridge in the road surface and which will not close up on the road material.

According to the invention two screed plates are butted together in end to end relation and are maintained in this butting relation at all times. The inner abutting ends of the screed plates are suspended from hangers which are capable of being drawn together or urged apart for raising and lowering the inner ends of the plates without however permitting any separation of the plates. In this manner the contour dened by the abutted platescan be varied at will to .control-the surface contour of the pavement. l

It is then an object of this invention to divide the screed assembly of road finishing machines into two units and to hinge these units together through a sealed joint which always maintains the screed plates in abutting relation.

A further object of the invention is to provide a screed assembly pivoted at its outer ends to a road finishing machine and divided'into individual units betweenthe outer pivot connections 1 with the machine for raising and lowering the inner ends of the units relative to their outer pivots to change the contour of the screed plates.

A further object ofthe invention is to provide a screed crown hinge which is sealed in all posithis thereof.

A still further object of the invention is toprovide a quickly adjustable screed assembly for road finishing machines capable of lchanging the contour in a road being laid without disassembly of parts of the machine.

Other and further objects of the invention will be apparent to those skilled in the art from the following detailed description of the annexed sheets of drawings in which:

Figure l is'a fragmentary side elevational view of a road finishing machine equipped with a screed assemblylaccording to this invention.

Figure 2 is a broken rear end elevational View of the machine shown in Figure 1.

Figure 3 is a fragmentary broken top plan view, with parts omitted, taken along the line III- III of Figure l.

Figure 4 is a diagrammatic rear endrview illustrating the manner in which the screed assembly is adjusted to crown the same.

Figure 5 is a vertical cross sectional view taken along the line V-V of Figure 6.

`IX---IX of Figure 1. l

Figure 10 is a vertical cross-sectional view taken substantially along the line X-X of Figure 2.

As shown on the drawings:

VIn Figure l the reference numeral l0 designates generally a road iinishing machine consisting of a self-propelled forward crawler unit A and a tamper and screed assembly B in spaced trailing relation from the crawler unit A. A space C bottomed by the road bed is thus provided between the units A and B.

'Ihe crawler unit A comprises a pair of crawler tracks such as Il and suitable framework dei-lning an engine platform l2 on which an engine I3 is mounted and a road material receiving platform I4 having ight conveyors mounted in the bottom' thereof (not shown) tc-move-material dumped therein out of the Qrear' end of Vtheunit into the space C. The front wall lZaof the engine platform I2 can have vertically adjustable gates thereon (not shown) acting as a strike-off or slice so that an even layer of road material will be fed by the flights to the space C.

Side arms such as I are pivotally mounted at their forward ends I6 to the unit A and extend rearwardly of the rear of the unit.

Screwrrods I1` are threadedv through brackets I'8 carried at the rear ends of the side arms I5 and are pivotally connected at their bottom ends to the outer rear ends of a screed assembly 2li- The forward outer end of thescreed assembly 2U is pivoted as at 2I to brackets such'as12'2- depending from the arms I5.

A'tamper assembly 23 (Fig. 1')- is mounteddirectly in front of the screed assembly 20 and is suspended on eccentrics from transverse shafts 24 (Figs. 1 and 3) which are driven through belt or chain connections from the engine I3 encased in housings 25 and 26. The tamperassembly is vibrated vertically toA tamp the materials fedto the space C as the finishing unit movesforward. The materials are -tamped into Ya nished mat of roadandthe screed assembly 2l).V rides over the mat to smooth andshape the same. Since the screed assembly Z'is suspended from the arms I5 the same will be vibrated by action .of the tamper assembly 23 on the roadmaterial. A deflector assembly 21 is mounted infront of the tamper assembly 23 and curvedv forwardly from the tamper assembly to keep the material in the space C rolling overv so` that it is agitatedv and again fed toY the-tamper. Distributing screws such.` asv 28 are suspended in the space Cr and serve to spread out the road material deposited therein.

Operators platforms 29 extend rearwardly from the screedassembly 20.

From the above description itfshould therefore be understood' that the screed assembly 20 is pivotedy atits outer forward ends' to brackets depending from the side arms I5. The rear outer ends of the screed assemblies are 4pivotally connected to the screw rods I1 which arey in threaded relation-withl brackets I8v on the rear ends of the sideV arms I5. Thus'theV rear end ofthe'screed assembly 20=can-be raised and loweredV by the screw rods IT about the pivots ZI. If, for example, the screw rods are raised' to raise the rear end of the screed' thev forward end or toe errdoflthe' screed will. converge downwardly'toward'thero'ad bed to decrease'th'e `thickness of the mat being laid by the machine. The inclined position ofthe screed will be temporary only: since as soon asthe mat' hasbeenthinned down to the desired amount the screedwillflatten out' about itspivot points andthe arms I5 will automatically lower to allowthe screed to assume its new lowerlevel.

According. to this invention the screedassembly 20`isi divided centrally` into right and left hand individualunitsia and 20h.

As best shown in Figures and 9V thewright and left hand screedunits 20a and Z'Ubare each built up fromtop plates 3i): supported through front walls such as 30a-secured to thefront ends of the screed plates 35. These front'walls 30afh'ave outer side-flanges 30h receiving the pivots' 2l (Figure 9*). Outer longitudinal stiiening beams 31 are carriedatthe'outerends ofthe, plates 30 and the forward ends' of these beams 3|(y carry bearings 32-'inV which the tamper shafts 24` are rotatably mountedas `shown in Figure 3'.

The". plates 30 also' carry inner longitudinal stiifening beams 35 spacedV inwardly from the beams 3|. These beams 33 likewise have bearings 34 thereon for the tamper shafts 24.

The screed units 20a and 20D each include a flat screed plate 35 adapted to ride on the pavement being laid. Each screed plate 35 has a vertical rear wall 35a secured thereto. Uprights 35 v(Figures 2v` and 10) extendbetWeen-the rear inner ends of the top plates 30 and the rear inner ends of the screed plates 35. Likewise diagyonal reinforcing struts 31 extend between the rear'ends-of the plates 30 and the rear ends of the-'screed plates 35. As shown in Figure 9, the upper ends of the struts 31 are secured towz-'ard'the-outer rear ends of the plates 30 while, as shown in Figure 2, the lower ends of these struts 31 are secured near the inner rear ends ofthe screed. plates;

The. platforms 29 are secured to the vertical vre'a'r'walls 35a'of the screed plates.

The rear` ends'vof the plates-3U are thussuppor-ted from the screed plates 35* through the uprights 36 and the diagonal struts31. The front endsof the p1ates3 arer supported by thefront Walls- 30a securedV to the fronts of the screed plates 35 and pivoted' to the side arm brackets 22.

Posts 38 and diagonals 39 (Figures2, 9 and; 10) likewisev extend upwardly from' the rear. walls 35a ofY the screed' plates tov support brackets.k 40 independentlyV of the plates 30; These. brackets 43 are'mounted immediately inrearv oftheplates 311v andA areheld in alignment by means of a brace lll'securedas at 42 to`one of' thebra'ckets only and extending across the rear'face of` the otherY bracket. The. brackets each have aperturedpivotpins'; 44 extending' tliereacrossl and a screw rod 43 is slidable through the pinsi A bushing 53 withia concaved seatportion is welded as at 53a= to one end of thescrew rodand its seat portionv engages the adjacent pinv 44. This prevents' rotation ofvv the;v screw rod. Additional bushings 53h are slidablyfmountednon the screw rod' to engageV theother` side of'theone pin 44 'andbothsid'esoff the other pin 44v as shown in Figure 5.

Lock nutsfsuchfasf45 are threaded onthescrew ro'df4'3to hold the adjacentbushings 53b'in position. A1ratchet device-46 threaded on the'screw rodbetween the brackets 43 acts on a thrust bearingMa abutting' a slidable' bushing 53h for forcing the brackets 40 apart. Since these brackets-4U are each rigidly connected to a rear wall35a'off asecreed plate 35 movement of the V brackets toward and awa'yfrom each other raises and` lowers the inner rear ends of the screed plates;

The screw rod'Y ratchet device 46 carries a sprocket 41 which-is connected through a chain 48 to a second sprocket 49 threaded on a second screw rod 56, as best shown in Figure 6 to act againstI the adjacent pins carried by brackets 52 which are supportedfby the beams 33.

In` Figures-5' and 8 the pins 44'carried by the brackets40 have transverse apertures 55 therethrough Which-'flare outwardly from the axis of the pins for a purpose to be hereinafter described.

Plates 56 disposed over thev beams 33' extend downwardlyin spaced opp'osedl relation a's-'shown in Figure 5 to the'screed plates 35; As indicated in Figure' 6 these plates 56 extend' rearwardly from the brackets 52v tol the` brackets-4U and to the rear endy of the lscreed platesl 352.-

When the sprockets 41 and 49 are operated on relation with each other along the screw rods 43 and 50 the plates 56 are forced apart and the plates together with the beams 33 and the brackets 40 may assume the angular positions shown in Figure 8. This angular position is readily permitted by the flaring 4bores 55 in the pins 44 as shown in Figure 8 without interfering with or binding against the screw rods.

The screed plates 35 are hinged together' as best shown in Figures 5 and?. Finger plates 60 are welded to the tops of the screed plates 35 adjacent their abutting inner ends. These plates 60 have alternating fingers 60a and 60h projecting therefrom over the opposite screed plate as shown in Figure 7. This arrangement prevents one plate 35 from rising above the Vother plate 35. The outer ends of the finger plates 60 are recessed as at 6|. Bars 62 have bottom flanges 63 adapted to nt in the recesses 6I. These flanges 63 have teeth 63a' on their inner ends to bite into and grip the finger plates 60;

The plates 56 depending from the screw rod controlled brackets 52 have feet or flanges 56a at their bottom ends welded on top of the finger plates Eiland as shown in Figures 5 and 7 these feet 56a project beyond the recesses in the finger plates 60 so that the `flanges 63 on the bars 62 cannot be pulled upwardly out of the recesses. As shown in Figure 5 the upper ends of the bars `62 have inwardly,projecting ribs l64 welded to the innerfaces thereof to form seats therebetween for a horizontal plate 65 bridging the space between the bars. The plates 56 are apertured as at 56h to receive the plate 65 therethrough.

Draw bolts 66 `extend through the bars 62 and through additional apertures in the plates 56 to draw the bars v62 together. Since these bars have flanges which act against the finger plates Eiland since the finger plates 60 are welded to the screed plates 35 tightening of the draw bolts will bring the screed plates into tight butting their entire inner adjacent edges. Y y

From the above description of the hinged joint between the screed plates it should be understood that the plates are held in proper vertical relation by means of interlocking fingers. The screed plates are held in tight abutting relation by drawbolts mounted very close to the screed surfaces. When the adjusting sprockets on the screw rods are operated to bring the plates 56 and the brackets 40 toward or away from each other the inner ends of the screed plates are raised or lowered while at the same time the abutting edges of the screedplates must rock in tight engagement with each other. A tightsealed joint between the plates is thus cbtained under` al1 conditions.

The crowning operation of the screed units 20a and 20h is illustrated diagrammatically in Figure 4 which shows in solid lines the position of the screed units when in -uncrowned or nat relation and showingin dotted lines the position of the screed units when in crowned relation.

It willbe noted from Figure 4 that the screed units are pivoted at their outer ends from supports carried by the side arms I5 of the machine. 'Ihe units are hinged together at the center through the stiff hinge designated generally at H and this hinge is raised and lowered by means of the plates 56 which are urged toward and away from each other through the adjusting screw 50. The rear screw rod 43 operated by the ratchet 46 thereon likewise moves the brackets 40 toward and away from each other to con- 75 trol the tilting of the rear ends of the screed plates. If the chain 48 is disconnected and the sprockets 41 and I94 independently operated the screed plates can be warped from front to rear as well as from outer end ot inner end. Thus with the plates in initial flat position the rear sprocket 41 can be operated alone to force the brackets 40 apart thereby producing a crown in the rear edge of the screed with no crown in the forward edge. This will throw the corners of the screed down so that it exerts more pressure at the edges. Adjustment of the front and rear brackets independently make for positive pressure control at any point inthe screed. Tearing or dragging tendencies can thus be eliminated at any point of the screed.

It is thus a simple matter to merely `operate the ratchet handle 46 on one of the adjusting screw rods and automatically obtain any desired amount of uniform crowning of the screed assemblies across their entire width or to vary the front to rear crown by independent operation of the screw rods. i i

It will, of course, be understood that various details of construction may be varied through a Wide range without departing from the principles of this invention and it is, therefore, not th 4purpose to limit the patent granted hereon otherwise then necessitated by the scope of the appended claims.

I claim as my invention:

1. A screed assembly for a material laying machine comprising side arms, pivots connecting the forward outer ends of the screed assembly with the side arms, screw rods depending from said side arms, pivots connecting said screw rods with the rear outer ends of the screed assembly, said screed assembly being divided centrally of said outer pivot connections into two units including abutting screed plates,A stiff rigid means secured to the screed plates and extending upwardly therefrom, adjustable spreading means extending between the stiff rigid means for moving said stiif rigid means toward and away from each other to raise and lower the inner ends of the units relative to their outer pivots, and a hinged joint between the screed units maintaining the screeds in abutting relation.

2. A screed assembly for a road nishing machine comprising a pair of screed plates in end to end abutting relation, a nger plate secured to the top of each screed plate adjacent the inner end thereof and having lingers extending over the other screed plate for holding the abutting ends in alignment,v bars engaging the outer ends of the finger plates, bolts drawing said bars toward each other to hold the screed plates in abutting relation, hangerplates secured to each finger plate and an adjusting spreading screw between the hanger plates for moving the same toward and away from each other'to tilt the screed plates about their abutting ends.

3. The improvements' in a screed assembly for a road finishing machine which comprise a pair of abutting screed plates, pivot supports for the outer ends of the screed plates, a hinge connection between the inner ends of the screed plates, means for raising and lowering said hinge connection relative to said Outer pivots for tilting the screed plates, independent bracket means connected to the rear ends of the screed plates, and means for moving said independent bracket means toward and away from each other to control the tilting of the rear ends of the screed plates relative to the tilted positions of the plates.y controlled by said means for' raising and lowering thehingeconnection.

4. A road finishing machine; including side arms, screw rods extending from said.. side g arms, a pair of screed plates in end to. end` relation, pivot connections between. the. outer rear ends of said screed plates, and said` screw. rods, brackets depending from said. side arms in spaced, forward relation from said screw rods, iront walls secured to the forward edges of-zy said screed plates, `pivot connections between the outer ends of said front walls and. said brackets, a hinged joint between the.V inner endsr of: said screed plates, means for raising and lowering said hinged joint to tilt they screed plates from their outer to their inner ends, brackets-secured tothe rear ends of the screed plates, and independent means for moving said brackets toward and away from each other to warp the.. screed plates in a front to rear direction.

5. A road` finishing machine includinga pair of spaced arms, a pair of abutting screedr plates in end to end relation pivotally` supportedat their outer ends from saidarms, a hingejoint connecting the inner'A abutting ends :ofv said'screed plates, means for raising and. lowering said hinge joint to tilt the screed plates from their outer to their inner ends, a bracket carried by thezrear end of each screed plate, a spreading screw rod extending between and connecting each of said brackets, and means for operating said' screwrod. tomove said brackets toward` and'awayA from each other for tilting therear ends: of said screed plates for crowning the same independently of the amount of tilt obtained by raising andrlowering said hinge.

6. In a crowning device for a screed assembly ofA a road finishing machine, the improvement which comprises individual screed plates, ahinge between said screed plates, a pair of opposed crown control brackets, hangers depending from said brackets. and secured to said hinge, and a spreading screwrod extending between the brackets for moving said. brackets toward and away from each other to tilt the hangers for raising andl lowering the hinge.

'7. A material laying'machine comprising a pair of. flat screed plates each extending inwardly; from opposite sides ofv the machine into abuttingfrelation with each other, drawbolts holding the4 inner edges of the screed plates in tightV abutment, and r means for raising and loweringsaid drawbolts to rock the screed platesY about their abutting edges for varying the contour of -a surface being laid by said; machine.

8. In a road finishing machine including-a pair of abutting screedplates, the improvement which comprises a hinge between-theabutting edges of said plates adapted for allowing rocking of the plates about their abutting edges, said hinge including plates secured to the topl of each respective screed plate and overlapping the opposite screed plate, and meansurging said overlapping plates toward each other.

,\ 9. A screed crown hinge for ascreed assembly ,including a pair of abutting screed plates, which comprises a finger plate welded to the top of each screed plate adjacent the abutted ends thereof, iingers projecting from said finger plates into overlapping relation with the opposite screed plate, bars disposed in angular relation to the screed plates having anges engaging the outer ends of the finger plates, a spacer plate between said 4bars in spaced relation above the screed plates, and drawbolts engaging said bars between the finger plates and said spacer plate for urging the bars together to act on the nger plates for holding the edges of the screed plates in tight abutting relation.

l0. In a screed assembly for a road finishing machine having two screed plates in abutted end toend relation, the improvement whichcomprises a bracket carried by the rear end of each screed plate, a screw rod extending between and operatively connecting each bracket, vand means for operating said screw rod to force the brackets apart for crowning. the rear ends of the screed plates.

V 11. In a road finishing machine including a screed assembly having a pairoi abutted screed plates in end to end relation, the improvement which compris-es a hinge including complementary parts fixed to each screed plate connecting the inner abutting ends of said plates, a hanger plate secured to each xed hinge part, brackets for cooperating with said hanger plates, a spreading screw rod between said brackets, and means for operating said screw rod to move the hanger plates away from each other for crowning the screed plates.

12. In a road nishing machine including a screed assembly having a pair of abutted screed plates in end to end relation, a hinged connection between the abutting ends of the screed plates, a pair of opposed brackets, hanger plates depending from said brackets secured to said hinge, a second pair. of opposed brackets carried by the rear-ends of the screed plates, screw rods connecting the brackets of each pair, and means connected to both screw rods for operating the screw rods in unison to move the brackets apart for crowning the screed plates.

13. A road finishing machine including spaced side arms, a pair of screed plates in end-to-end abutting relation pivotally supported at their outer ends from said side arms, a hinged joint construction between the inner ends 0f said screed plates including complementary hinge parts fixed to each screed plate, laterally spaced brackets above said hinged joint construction, a hanger eX- tending from each bracket to a complementary hinge part, a spreading screw rod between the brackets, means for operating the screw rod to move the brackets toward and' away from each other for raising and lowering the hangers to move the hinged joint construction relative to the pivot supports at the outer ends ofthe screed plates for thereby tilting the screed plates from the outer to the inner ends thereof.

HARRY H. BARBER. 

